Flexible and conformal patch pump

ABSTRACT

Provided is a flexible and conformal wearable, self-contained medical device. The medical device comprises an integral housing formed by a flexible upper portion and a flexible lower portion joined along their perimeters. The medical device is also provided in a plurality of shapes and configurations for increasing the flexibility and conformability of the housing. The components contained within the housing, such as a drug reservoir, printed circuit board, and power supply are preferably constructed from flexible materials and are formed, connected and positioned according to the configuration of the housing in a manner for enhancing flexibility of the housing. A thermal bubble micropump is provided for controlling flow of a drug from the flexible reservoir, that utilizes a thermal resistor provided locally to a thermal expansion fluid that causes a surrounding membrane to expand and displace a volume of drug to be provided to the user.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a division of U.S. patent application Ser. No.12/585,062, filed Sep. 2, 2009, which is incorporated herein in itsentirety.

FIELD OF THE INVENTION

The present invention relates generally to wearable, self-contained druginfusion devices provided in a discreet flexible and conformal housingfor providing greater comfort, convenience, ease of use, andattractiveness for the user.

BACKGROUND OF THE INVENTION

Diabetes is a group of diseases marked by high levels of blood glucoseresulting from defects in insulin production, insulin action, or both.There are 23.6 million people in the United States, or 8% of thepopulation, who have diabetes. The total prevalence of diabetes hasincreased 13.5% since the 2005-2007 time period. Diabetes can lead toserious complications and premature death, but there are well-knownproducts available for people with diabetes to help control the diseaseand lower the risk of complications.

Treatment options for people with diabetes include specialized diets,oral medications and/or insulin therapy. The primary goal for diabetestreatment is to control the patient's blood glucose (sugar) level inorder to increase the chances of a complication-free life. It is notalways easy, however, to achieve good diabetes management, whilebalancing other life demands and circumstances.

Currently, there are two principal modes of daily insulin therapy forthe treatment of type 1 diabetes. The first mode includes syringes andinsulin pens that require a needle stick at each injection, typicallythree to four times per day, but are simple to use and relatively low incost. Another widely adopted and effective method of treatment formanaging diabetes is the use of an insulin pump. Insulin pumps can helpthe user keep their blood glucose levels within target ranges based ontheir individual needs, by continuous infusion of insulin. By using aninsulin pump, the user can match their insulin therapy to theirlifestyle, rather than matching their lifestyle to how an insulininjection is working for them.

Conventional insulin pumps are capable of delivering rapid orshort-acting insulin 24 hours a day through a catheter placed under theskin. Insulin doses are typically administered at a basal rate and in abolus dose. Basal insulin is delivered continuously over 24 hours, andstrives to keep one's blood glucose levels in a consistent range betweenmeals and overnight. Some insulin pumps are capable of programming thebasal rate of insulin to vary according to the different times of theday and night. Bolus doses are typically administered when the usertakes a meal, and generally provide a single additional insulininjection to balance the carbohydrates consumed. Some conventionalinsulin pumps enable the user to program the volume of the bolus dose inaccordance with the size or type of the meal consumed. Conventionalinsulin pumps also enable a user to take in a correctional orsupplemental bolus of insulin to compensate for a low blood glucoselevel at the time the user is calculating a meal bolus.

There are many advantages of conventional insulin pumps over othermethods of diabetes treatment. Insulin pumps deliver insulin over timerather than in single injections and thus typically result in lessvariation within the blood glucose range that is recommended by theAmerican Diabetes Association. Conventional insulin pumps reduce thenumber of needle sticks which the patient must endure, and make diabetesmanagement easier and more effective for the user, thus considerablyenhancing the quality of the user's life. Insulin pumps however can beheavy and cumbersome to use and are typically more expensive than othermethods of treatment. From a lifestyle standpoint, the conventionalpump, tubing, and infusion set are inconvenient and bothersome for theuser.

New advances in insulin therapy provide “wearable” drug infusiondevices, such as patch pumps, that are lower in cost and are somewhatmore convenient and comfortable to use than conventional insulin pumps.Some of these devices are intended to be partially or entirelydisposable, and in theory provide many of the advantages of conventionalinsulin pumps without the initial high cost and inconvenience ofconventional insulin pumps. Commonly available patch pumps, however,still do not provide the user with the utmost comfort and convenience tolend themselves to more widespread use. Typical patch pumps are stillrelatively heavy and bulky and are commonly constructed with a rigidhousing containing rigid components, thus causing the user discomfortover a prolonged period of use. Such patch pumps tend to be especiallyuncomfortable for children, small women and the elderly, for whom therelatively large patch pumps are not ideal. Additionally, theconstruction of common patch pumps prevents the patch pump from beingeasily concealed and limits the number of locations on a user's bodywhere it may be worn.

Accordingly, there is a need for more discreet drug infusion deviceswith improved convenience, comfort, and wearability, so that many moreusers may benefit from the advantages these devices provide.

SUMMARY OF THE INVENTION

Exemplary embodiments of the present invention address at least theabove problems and/or disadvantages and provide at least the advantagesdescribed below. Accordingly, it is an object of certain embodiments ofthe present invention to provide more discreet, flexible and conformal,wearable drug infusion devices for increasing a user's convenience andcomfort in using such devices.

According to one aspect of the present invention, a wearable medicaldevice provided for administering drug therapy to a user comprises anintegral housing containing a flexible reservoir for housing a supply ofa drug, in fluid communication with an infusion cannula for deliveringthe drug to the user, and a fluid metering device for metering deliveryof the drug from the reservoir to the user through the infusion cannula,wherein said housing comprises a flexible upper portion and a flexiblelower portion that are sonically welded together along their respectiveperimeters. The upper and lower portions of the housing are constructedfrom a flexible polymer wherein the thickness of the integral housing iswithin a range of 0.25 to 1.25 inches, preferably no more than about0.75 inches, and is affixed to the user's skin with an adhesive layer. Afoam or elastomer layer may also be provided sandwiched between theadhesive layer and the lower portion of the medical device. The fluidmetering device comprises at least one thermal resistor provided locallyto a thermal expansion fluid encapsulated by a flexible membrane,wherein heating of said thermal expansion fluid causes expansion of saidflexible membrane resulting in displacement of the drug and actuation ofsaid drug into said user through the infusion needle. In one embodiment,a plurality of thermal resistors with expansion fluid and flexiblemembrane may be provided sequentially to create a linear peristaltictype flow of said drug to the user. The fluid metering device furthercomprises at least one one-way check valve for promoting a flow of thedrug to said user. The fluid metering device may also comprise anelectronically controlled gate or valve for controlling the flow of drugto said user. In one embodiment, the fluid metering device alternativelycomprises one of a Belleville spring washer, stamped leaf spring, snapdisk or flexure, for expelling the drug from said reservoir. The medicaldevice further contains a flexible circuit board, provided with at leastone recess extending inwardly from an outer edge of said circuit board,for electronically connecting at least the fluid metering mechanism witha controller.

According to this aspect of the present invention, the medical device isprovided comprising a chassis, the chassis comprising at least a firstframe flexibly connected to a second frame for positioning a firstsystem component in said first frame and a second system component insaid second frame relative to each other in said housing. The medicaldevice further comprises an infusion needle deployment mechanismactuated by a push button deployable within said housing, wherein in oneembodiment, said needle deployment mechanism comprises a spring disk fordriving said infusion needle into the user. In another embodiment, theneedle deployment mechanism comprises a torsion spring actuated by afinger lever for driving said infusion needle into the user. In yetanother embodiment, the needle deployment mechanism comprises a needlecarriage and a cannula carriage initially engaged with each other fordriving a flexible cannula into the user using an insertion needle, anda spring member for withdrawing said insertion needle from the user uponinsertion of said flexible cannula into the user. A similar needlecarriage and biosensor carriage is also provided for inserting abiosensor into the user with the aid of an insertion needle, whereuponthe needle is withdrawn from the user after insertion of the biosensor.The medical device also comprises a mechanism for manually actuating abolus dose by applying a force to a specific area on said upper portionof said housing and a mechanism for deploying a transcutaneous analytesensor for the purpose of determining the blood glucose level of theuser, or some other physiological indicator.

Still according to this aspect of the invention, a second flexiblereservoir is provided for housing a volume of drug for bolus dosedelivery to the user. The second reservoir may be provided in fluidcommunication with a second infusion cannula and is preferably used foradministering drug therapy to a user with type 2 diabetes. Additionally,the medical device in this embodiment provides a basal rate of druginfusion to the user and may be used in conjunction with a programmableinjection device, such as an insulin pen, for providing bolus dose drugtherapy. The programmable injection device is preferably programmed by ahost device which also calculates the bolus dose of drug for injectioninto the user.

A second aspect of the present invention provides a wearable medicaldevice for administering drug therapy to a user, comprising an integralhousing comprising a flexible upper portion and a flexible lowerportion, wherein said housing is formed into an elongate shapecomprising a length dimension that is longer than a width dimension, andfurther comprising a waist portion that is narrower than the widthdimension, said housing being contoured such that the housing isnarrowest at the waist portion. The flexible upper and lower portions ofthe medical device are sonically welded together along their respectiveperimeters.

A third aspect of the present invention provides a wearable medicaldevice for administering drug therapy to a user, comprising an integralhousing comprised of a flexible upper portion and a flexible lowerportion, wherein said upper and lower portions comprise at least onerecess extending inwardly from an outer edge of each of said upper andlower portions. The medical device further comprises a second recessextending inwardly from an outer edge of each of said upper and lowerportions at a location opposite the at least one recess. The first andsecond recesses of the upper and lower portions define a flex regionthat separates a first area of the device from a second area of thedevice. A first system component is contained within the first area anda second system component is contained within the second area.

Yet another aspect of the present invention provides a wearable medicaldevice for administering drug therapy to a user, comprising an integralhousing comprised of a flexible upper portion and a flexible lowerportion, wherein said housing comprises a central hub area with aplurality of lobes extending radially from said central hub. A firstsystem component of the medical device is contained within a first lobe,and a second system component is contained within a second lobe. Thefirst system component and the second system component include one of areservoir for delivering a bolus dose of a drug, a biosensor, a needledeployment mechanism, and a communication transceiver. The medicaldevice further comprises at least one adhesive pad attached to a skinattachment side of said plurality of lobes.

A final aspect of the present invention provides a method for providinga flexible, wearable medical device for administering drug therapy to auser, by preparing a housing comprising an upper flexible portion and alower flexible portion, providing within said housing, an infusioncannula in fluid communication with a reservoir for housing a drug to beadministered to the user and a fluid metering mechanism that meters avolume of the drug administered through the infusion cannula, andforming the housing by connecting the upper flexible portion to thelower flexible portion along a perimeter of each. The method sonicallywelds the upper flexible portion to the lower flexible portion.

Objects, advantages and salient features of the invention will becomeapparent to those skilled in the art from the following detaileddescription, which, taken in conjunction with annexed drawings,discloses exemplary embodiments of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other exemplary features and advantages of certainexemplary embodiments of the present invention will become more apparentfrom the following description of certain exemplary embodiments thereofwhen taken in conjunction with the accompanying drawings, in which:

FIG. 1 is a block diagram illustrating the principal components of amedical device in accordance with an exemplary embodiment of the presentinvention;

FIG. 2 is an illustration of a first exemplary embodiment of a medicaldevice in accordance with an exemplary embodiment of the presentinvention;

FIGS. 3A-3C illustrate a second exemplary embodiment of a medical devicein accordance with an exemplary embodiment of the present invention;

FIG. 4 is an illustration of a third exemplary embodiment of a medicaldevice in accordance with an exemplary embodiment of the presentinvention;

FIGS. 5A-5B illustrate of a fourth exemplary embodiment of a medicaldevice in accordance with an exemplary embodiment of the presentinvention;

FIGS. 5C-5D illustrate an exemplary embodiment of an adhesive layer foruse in any of the exemplary embodiments of a medical device;

FIGS. 6A-6C illustrate an exemplary embodiment of a pump mechanism foruse in any of the exemplary embodiments of a medical device;

FIGS. 6D-6H illustrate an additional exemplary embodiment of the pumpmechanism shown in FIGS. 6A-6C for use in any of the exemplaryembodiments of a medical device;

FIG. 7 illustrates another exemplary embodiment of a pump mechanism foruse in any of the exemplary embodiments of a medical device;

FIG. 8 illustrates a third exemplary embodiment of a pump mechanism foruse in any of the exemplary embodiments of a medical device.

FIG. 9 illustrates a fourth exemplary embodiment of a pump mechanism foruse in any of the exemplary embodiments of a medical device.

FIG. 10 illustrates a fifth exemplary embodiment of a pump mechanism foruse in any of the exemplary embodiments of a medical device.

FIGS. 11A-11E illustrate exemplary embodiments of a needle deploymentmechanism for use in any of the exemplary embodiments of a medicaldevice.

FIGS. 12A-12D illustrate another exemplary embodiment of a needledeployment mechanism for use in any of the exemplary embodiments of amedical device.

FIGS. 12E-12H illustrate an exemplary embodiment of a sensor deploymentmechanism for use in any of the exemplary embodiments of a medicaldevice.

FIGS. 121-12J illustrate an exemplary embodiment of a manually actuatedcannula deployment mechanism with a user controlled carriage for use inan exemplary embodiment of the present invention.

FIGS. 13-15 illustrate additional embodiments of a medical device inaccordance with an exemplary embodiment of the present invention.

FIG. 16 illustrates an additional embodiment of a drug delivery devicein accordance with an exemplary embodiment of the present invention.

Throughout the drawings, like reference numerals will be understood torefer to like elements, features and structures.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

The matters exemplified in this description are provided to assist in acomprehensive understanding of exemplary embodiments of the invention,and are made with reference to the accompanying figures. Accordingly,those of ordinary skill in the art will recognize that various changesand modifications of the exemplary embodiments described herein can bemade without departing from the scope and spirit of the claimedinvention. Also, descriptions of well-known functions and constructionsare omitted for clarity and conciseness.

A general embodiment of medical device 100 is illustrated in FIG. 1.Medical device 100 is preferably a wearable medical device provided forthe delivery of a liquid or gel medication, preferably but notnecessarily insulin, or other therapeutic substance, by continuousinfusion into or through the skin of the patient. Medical device 100 iscapable of providing subcutaneous, intradermal, intramuscular andintravenous infusion of the drug or substance. Such known medicaldevices are commonly referred to as “patch pumps” due to their nature ofbeing worn or affixed to the user's skin. Medical device 100 generallycomprises a housing for a flexible drug reservoir 106 or other containerfor supplying a drug, an infusion needle deployment mechanism 108 and apump mechanism 114 or fluid metering device for controlling the deliveryof the drug into the user's body through an infusion needle provided inthe infusion needle deployment mechanism 108. Medical device 100 alsopreferably comprises a microprocessor or controller 116 for directingthe infusion needle deployment mechanism 108 and pump mechanism 114 aswell as monitoring and/or controlling other preferred operations andsystems of medical device 100, and a power supply 118 such as any knownpower source including, but not limited to, a disposable or rechargeablestandard battery, capacitor, or energy harvesting system such as thatdisclosed in commonly assigned and co-pending U.S. patent applicationSer. No. 12/458,807, filed Jul. 23, 2009, which is incorporated hereinby reference in its entirety.

One exemplary embodiment of medical device 100 is a pre-programmed patchpump. The pre-programmed patch pump can be programmed either by themanufacturing facility or a health care provider and preferably requiresno additional user programming. A pre-programmed patch pump is ideal forcertain patient groups, such as recently diagnosed type 1 diabetics,more specifically those that are elderly or mentally challenged and mayhave difficulty in programming the patch pump. Pre-programmed patchpumps may comprise simple intelligence for providing a customized basalinfusion rate that can be varied throughout the day to match sleepingand waking insulin requirements. The preprogrammed patch pump can beprogrammed to deliver drug to the user at different rates for differenttimes of day or under different conditions. Varying drug delivery ratesover time are referred to herein as a drug delivery profile. Thepre-programmed patch pump may also be designed with mechanization toenable manual actuation of an incremental bolus dose, for example 10units. One form of manual actuation would require the closure of anelectrical contact, such as a momentary switch or two momentaryswitches, for an extended duration. A separate second reservoir may beprovided for supplying the bolus dose, and could utilize either the samecannula used for basal infusion or a second cannula. A pre-programmedpatch pump may also be configured to provide multiple daily injections.

Medical device 100, in other embodiments of the present invention, mayalso be provided as a fully-programmable (“smart”), or substantiallymechanical(“simple”) package, as would be appreciated by one of ordinaryskill in the art.

A fully-programmable “smart” patch pump provides the user with thegreatest precision and flexibility in controlling the rate ofadministering a drug that is suitable for the user's lifestyle, but addsadditional cost and complexity to the device. “Smart” patch pumps aregenerally used in conjunction with a Blood Glucose Monitor (BGM) and ahost device, such as a Personal Diabetes Monitor (PDM), to provide,through closed-loop control and sensing, a customized basal infusionrate and bolus doses that may be activated or adjusted at any timethroughout the day. “Smart” patch pumps are preferably configured to bein communication with the host device, such as via a personal areanetwork as described in previously incorporated, co-pending U.S. patentapplication Ser. No. 12/458,807, or via a wireless network. “Smart”patch pumps may also communicate, continuously or intermittently, withthe host device via a wired or other direct connection.

“Simple” patch pumps can be provided with minimal or no systemintelligence and generally comprise mostly mechanical systems forproviding basic control of insulin infusion through either a presetbasal rate or manually activated bolus doses. The cost of “simple” patchpumps is greatly reduced compared to “smart” patch pumps, since therelatively expensive electronics necessary for realizing the specializedsensing, control and communication capabilities are not required.

Each patch pump package, “smart”, pre-programmable, and “simple”, isparticularly effective and desired for a certain type of user or groupof users. A user's lifestyle, medical condition, financial situation andaptitude for operating a medical device largely determine which packageof patch pump is suitable for that user. The specific features andfunctionality of exemplary embodiments of the present invention, tofollow, may be implemented in each of the patch pump packages describedabove. Additional embodiments, features and specific functionality ofpatch pumps to be used in accordance with the present invention can befound in U.S. Pat. No. 6,960,192 and U.S. Patent Application PublicationNo. 2004/0010207, both assigned to Insulet Corporation, commonlyassigned U.S Pat. No. 6,589,229 issued to Robert I Connelly, et al., andcommonly assigned co-pending U.S. Patent Application titled “ExtendedUse Medical Device,” filed on even date herewith (attorney docket numberP-8618(55579)), which are all incorporated herein by reference.

Exemplary embodiments of medical device 100 in accordance with thepresent invention are illustrated in FIGS. 2-5. Each of the exemplaryembodiments depicted therein comprise a flexible upper and lower cover,shown as 202 and 204 in FIGS. 2, 302 and 304 in FIGS. 3A and 3C, 402 and404 in FIGS. 4, and 502 and 504 in FIG. 5A. In the exemplary embodimentsof the present invention, the upper and lower covers make up an externalshell or housing for medical device 100. Each of the upper and lowercovers is preferably constructed from thin flexible polymers, such aspolyethylene (PE), polypropylene (PP), or polyvinyl chloride (PVC).These materials are exemplary and are not intended to be limiting, andone of ordinary skill in the art will recognize that any suitablematerial for providing a thin flexible housing for the components ofmedical device 100 may be used. The upper and lower covers arepreferably substantially similar in shape, so as to have matching ornear matching perimeters. In an exemplary embodiment, the upper andlower covers are sonically welded together along the perimeter of eachto securely encapsulate the components of medical device 100. The lowercover is preferably affixed to the user's skin via any well known,long-lasting adhesive layer 210 that is safe for skin contact with theuser. As the lower cover of medical device 100 is affixed to the user,the lower cover conforms to the user and advantageously permits flexureof the entire medical device 100. The upper cover is preferably designedto minimize imparting resistance to the flexure and conformity ofmedical device 100. A housing for medical device 100 constructed in thismanner is very thin, flexible and conformal to each user's unique bodyshapes. The minimal thickness and optimal flexibility of medical device100 affords the user a level of convenience, versatility and comfort,not provided by conventional patch pumps.

It is also preferred, in exemplary embodiments of the present invention,that the chosen shape of the upper and lower covers be visiblyattractive to the user and the public so as to enhance the overallperception of an exemplary medical device 100. To conceal thefunctionality of medical device 100, the upper cover may be designed toresemble a common bandage, or may be colored to blend with a user's skintone. Additionally, the upper cover of each embodiment may be decoratedwith a custom design, artwork, or logo, to further enhance a visualappeal of the device for the user and signify a user's individuality,especially when worn by a child.

The upper cover, in exemplary embodiments of the present invention, maybe constructed to be slightly hardened, thicker, or more durable thanthe lower cover, in order to provide added protection for the internalcomponents. To ensure optimal flexibility of medical device 100, it isnot necessary that the entire surface of the upper cover be constructedin this manner. For instance, as shown in FIG. 2, part of the uppercover 202 with a smaller surface area 203 in a similar shape as theupper cover, may be constructed in the above manner to provide the addedprotection. In another embodiment, select areas of the upper cover maybe constructed in this manner to provide added protection only tospecific portions or components of medical device 100.

FIGS. 2 and 3 illustrate first and second exemplary embodiments ofmedical device 100 that provide two-dimensional conformity andflexibility in accordance with the present invention. The embodimentdepicted in FIG. 2 is an elongate flexible medical device 200 thatrealizes a minimal thickness, but also provides increased surface areafor skin adhesion to a user. The design of flexible upper cover 202 andflexible lower cover 204 provide increased conformity to cylindricalshapes, such as a user's arm. Flexibility and conformity of medicaldevice 200 shown in FIG. 2 is increased by providing a “waist” 205 orreduced dimension of the mid-section of the elongate upper and lowercovers. The medical device 200 has a length dimension defined as thelongest dimension extending from a first edge 220 of the cover to asecond opposite edge 222 of the cover. The medical device 200 has awidth dimension defined as a longest dimension that is perpendicular tothe primary dimension and spans from a third edge 221 to a fourth edge223 of the cover opposite the third edge. The width of the device 200 ispreferably contoured to be narrower at a midsection or “waist” 205. Inthe embodiment shown, the waist dissects the device 200 forming a firstsection 207 and a second section 209 opposite the first section, thatare preferably symmetrical about the waist, such that the first andsecond section are of a similar shape and dimension.

The overall shape of upper cover 202 and lower cover 204 for medicaldevice 200 in an exemplary embodiment illustrated in FIG. 2, is notspecifically limited to the shape depicted. Alternate shapes andrelative dimensions of upper cover 202 and lower cover 204, suitable foruse in this embodiment, will be understood by one of ordinary skill inthe art. For instance, in another embodiment, instead of providing the“waist” 205 or reduced section midway along the length dimension of theupper and lower covers, as shown in FIG. 2, the flexible upper and lowercovers may comprise at least one waist section at any point along thelength dimension. This waist section preferably comprises a dimensionthat is perpendicular to the length dimension and less than the widthdimension. In this embodiment, it is not necessary that the upper andlower covers comprise a first and second section symmetrical about theat least one waist section, or that the waist section even dissects afirst section and a second section equally. One of ordinary skill in theart will understand that any shape of a flexible upper and lower cover,202 and 204, that is defined by the description provided above may besuitable for medical device 100 in the first exemplary embodiment.

Exemplary embodiments of the present invention, as illustrated in FIGS.2-5, provide not only a flexible housing for medical device 100, asdiscussed above, but also preferably utilize flexible and low profilecomponents within the housing to be specifically described furtherbelow, such as a flexible reservoir 106, flexible circuit board 216,flexible power supply 118, flexible electrical conductors betweencomponents, and low profile pump mechanism 114 and infusion needledeployment mechanism 108. The profile of medical device 100 may range inthickness from 0.25 inches to 1.25 inches, but is preferably no greaterthan 0.75 inches, depending on the specific functionality of medicaldevice, that is, whether it is “smart”, pre-programmed, or “simple”, aswell as the specific components chosen for needle deployment mechanism108 and fluid metering mechanism 114, and the arrangement of suchcomponents. The specific components illustrated in FIG. 2 are notlimited to this exemplary embodiment of the present invention and one ofordinary skill in the art will recognize that any combination andarrangement of components may be utilized in each of the exemplaryembodiments illustrated and described with respect to FIGS. 2-5.

The flexible and conformal medical device 300 illustrated in FIGS.3A-3C, is formed into a substantially rectangular package that resemblesa familiar bandage, with a reduced surface area of coverage butincreased thickness relative to the embodiment illustrated in FIG. 2.Flexible upper cover 302 and flexible lower cover 304 preferably provideoptimal flexibility and conformity, as discussed above. Since theoverall surface area or footprint of the flexible upper cover 302 andflexible lower cover 304 in this embodiment are reduced, it is notnecessary to provide a reduced “waist” or midsection for aiding inconformity or flexibility. However, due to the reduced surface area ofmedical device 300, several of the desired components may be stacked orarranged on top of each other, as shown in FIG. 3C, resulting in theincreased thickness of medical device 300. To maintain overallflexibility and conformity of medical device 300, it is necessary thatthe arrangement of the components do not inhibit the desired flexure ofmedical device 300, as will be described in further detail below.

The exemplary embodiment illustrated in FIG. 3A provides an exemplaryflexible printed circuit board (PCB) 316 and a flexible chassis 322 forproviding a flexible arrangement of the specific system components,ideal for use in medical device 100 with a reduced surface area asdescribed above. The exemplary embodiment of a flexible printed circuitboard 316 for use in this and other exemplary embodiments is shown inFIG. 3A. Flexible PCB 316 is modified in this embodiment to includeslots, recesses or cutouts, 316 a and 316 b along the outer perimeter ofPCB 316, as shown. This modification provides an additional degree offlexibility for the PCB 316 at locations that are preferably locatedbetween rigid system components, so as to enable the PCB to flex asnecessary based on the close positioning of the other system components,as shown in FIG. 3C. It should be understood by one of ordinary skill inthe art that the embodiment shown in FIGS. 3A-3C is provided merely forillustration, and to help understand the concepts which enhance theflexibility and conformity of a medical device. The number of cutouts,316 a and 316 b, the dimensions of such cutouts, and the placement ofthe cutouts on the PCB 316 are preferably selected based on the specificnumber and layout of components in a particular embodiment and are notlimited by the exemplary embodiment illustrated in FIG. 3A.

FIGS. 3A and 3B illustrate a flexible chassis 322 for use in exemplaryembodiments of the present invention. For efficient operation of medicaldevice 300, it is preferred that at least the reservoir 106, pumpmechanism 114 and infusion needle deployment mechanism 108 all belocated reasonably adjacent to each other. However, arranging suchcomponents too closely may result in an undesirable rigidity in theoverall flexure of medical device 300. Flexible chassis 322, as shown inFIG. 3B, is provided to preferably house at least a low profile needledeployment mechanism 108 and pump mechanism 114. Chassis 322 comprisesat least a first and second frame, 324 and 326, for holding therespective components in position relative to each other. A thirdoptional frame 328 is shown, which in some embodiments may house asecond needle deployment mechanism, a transcutaneous analyte sensor orbiosensor, or any other components as will be understood by one ofordinary skill in the art. FIG. 3B illustrates how each of therespective frames, 324, 326 and 328, are maintained in relation to eachother by flexible joints 322 a molded to each of the connected frames.The interconnection of the system components using flexible joints 322 aon chassis 322 serves to effectively hold the respective systemcomponents in relation to each other, while providing flexibilitybetween the components of medical device 300. FIG. 3C is a cross sectionof medical device 300, illustrating the relative positioning and flexureof chassis 322 and PCB 316, in an exemplary embodiment of the presentinvention. One of ordinary skill in the art will appreciate that therelative dimensions and number of frames flexibly interconnected to eachother are not limited by the illustrations in FIGS. 3A-3C, and aremerely provided as examples.

FIGS. 4 and 5A-5B illustrate third and fourth exemplary embodiments of amedical device 400 that provide additional degrees of flexibility foreasily conforming to complex shapes. Similar to the modification of PCB316 in FIG. 3, the flexible upper and lower covers of medical device400, in an exemplary embodiment of the present invention, may bedesigned with slits, cutouts or recesses, 402 a and 402 b, along theperimeter of each. The number, size, and placement of recesses 402 a and402 b illustrated in FIG. 4 is merely exemplary. The upper and lowercovers, according to this exemplary embodiment, preferably comprise atleast one inward extending recess 402 a provided along the perimeter ofeach cover. The at least one recess is preferably but not necessarilyprovided with a second similar recess 402 b at the opposite edge of thecover. The coordinating recesses preferably, effectivelycompartmentalize medical device 400, into modules 403 a, 403 b and 403c, and provide an added dimension of flexibility and conformity to themedical device for enabling a comfortable placement of medical device400 on complex contours of a user's body.

The compartments or modules depicted in FIG. 4 preferably house at leastone system component, such as the battery supply 118 in module 403 a,flexible reservoir 106 and pump mechanism 114 in module 403 b andflexible PCB 416 in module 403 c. Ideally, but not necessarily, anentire component will be positioned inside a single compartment ormodule. By positioning the system components within the compartments, asillustrated in FIG. 4, preferably only a flexible connection extendsfrom one compartment to the next. The area of greatest flexibility andconformity of medical devices 400 is where the individual compartmentsconjoin. Thus, by positioning the system components in the separatecompartments, maximum flexibility and conformity of medical device 400may be realized.

FIGS. 5A and 5B illustrate a fourth exemplary embodiment of amulti-dimensionally flexible medical device 500 that is alsocompartmentalized into modules or lobes and even further enhances themulti-dimensional conformity of the medical device. The upper and lowercovers, 502 and 504, of medical device 500 preferably comprise a central“hub” area 503 of arbitrary shape and dimension with a plurality ofmodules or lobes 505 a-505 d, also of arbitrary shape, that extendradially from the central hub 503. Similar to the exemplary embodimentdescribed in FIG. 4, medical device 500 preferably houses at least onesystem component in each of the lobes 505 a-505 d and the central hub503. Ideally, but not necessarily, each lobe will entirely incorporatethe system component positioned therein. Since medical device 500 ismost flexible and conformal near the area where each of lobes 505 a-505d conjoin the central hub area 503, it is preferred, where possible,that only a flexible connection extend from each lobe 505 a-505 d to thecentral hub 503. It is preferred, in exemplary embodiments of thepresent invention, that the specific components are arranged and shapedso as to adopt the overall or compartmental shape and mode of flexure ofthe upper and lower covers, such as the flexible PCB 516 shown in FIGS.5A and 5B adopting the shape of central hub area 503, as well asflexible PCB 416 depicted in FIG. 4.

The specific components shown in FIGS. 5A-5B, as being contained withinmedical device 500, are provided only by example, and are not intendedto be limiting. One of ordinary skill in the art will understand thatthe specific components and arrangement of components within the medicaldevice 500 and especially within the individualized compartments willvary depending on the intended functionality of medical device 500. Anycombination of components necessary for realizing a desiredfunctionality of medical device 500 may be advantageously chosen andpositioned within the flexible housing to achieve maximum flexibilityand conformity of medical device 500. Additionally, the shape of upperand lower covers, 502 and 504, as shown in FIGS. 5A and 5B, is notlimiting of exemplary embodiments of the present invention. One ofordinary skill in the art will understand that the device may be formedinto any suitable shape that is flexible and conformal to the user'sbody.

The embodiment illustrated in FIG. 5A, provides an additional level ofcomfort for the user in addition to that achieved by the flexibledesign. As shown in FIG. 5A, lower cover 504 is preferably affixed tothe user's skin with adhesive pads 510 provided on each of the radiallyextending lobes 505 a-505 d. In contrast, common patch pumps typicallyprovide an adhesive layer that substantially covers the entire surfacearea of the portion of housing that is affixed to the user. Some user'sskin may be particularly sensitive to the adhesive that is used and manyusers often find that it is somewhat painful to remove the medicaldevice after a desired duration of use. Additionally, the adhesive layerused in common patch pumps does not enable the natural stretching orflexing of a user's skin in the area on which the adhesive is applied.Users often complain of discomfort from a feeling that their skin isbeing pulled as a result of the large surface area of the adhesive layerimpeding the natural stretching and flexing of a user's skin. Theseparate adhesive pads 510, as shown in FIG. 5A, reduce the totalsurface area of the user's skin on which the adhesive is applied, andallow the user's skin between the pads to stretch more comfortably, thusminimizing any potential skin irritation and pain associated with theuse of medical device 500.

In other embodiments, the adhesive layer for use with exemplaryembodiments of a medical device may adopt a pattern that enhancesflexibility along the perimeter of the medical device for enablingincreased freedom of movement at the interface of the user's skin andthe exemplary medical device, such as a zig-zag pattern. For instance, apattern 511 as shown in FIG. 5C for use with the medical device shown inFIG. 5, may be used in exemplary embodiments. A similar pattern may beadopted for use with any shape of the above described exemplary medicaldevices, as would be understood by one of ordinary skill in the art.Such a pattern reduces a user's awareness of the physical sensationaccompanied by the adhesive interface and enables flexibility byallowing subtle movement to occur on the surface of the skin duringnormal physical activity. The adhesive layer is also preferably formedor formulated from a flexible material so as to enable subtle stretchingof the adhesive layer, thus further enhancing comfort and flexibility ofthe medical device. It is preferred, that the freedom of movementprovided by such an adhesive is subtle and should not cause undesirablemovement at the infusion site. Nevertheless, in one embodiment, anadditional non-flexible adhesive ring or perimeter, acting as an anchor,may be provided at the infusion site for preventing any undesirablemovement at this site. Additional embodiments of the present inventionmay also comprise an adhesive layer of any desired shape or size with anincreased thickness, or an elastomer or foam layer 512 sandwichedbetween the adhesive layer and the medical device, as shown in the sideprofile of medical device 500 depicted in FIG. 5D, for providingadditional freedom of movement and flexibility. The thickness of layer512 is preferably chosen to provide an increased overall flexibility ofan exemplary medical device without overly increasing the profile of themedical device while affixed to the user's skin. The above embodimentsare not limited to the medical device 500 as shown, but may be providedwith any of the above exemplary medical devices.

The specific components and arrangement of the components that aredepicted in FIGS. 2-5 are not meant to be limiting, and are provided toillustrate concepts of various embodiments of the present invention.Medical devices according to exemplary embodiments of the presentinvention may incorporate any combination of the components to bediscussed below, as well as any other components available in the artfor realizing specific functionality of a wearable medical device. Thespecific components are preferably provided in any advantageousarrangement for enabling a thin, flexible, conformal medical device, aswill be understood by one of ordinary skill in the art.

Controller 116, as shown in FIG. 1, in an exemplary embodiment of thepresent invention, is provided at least for controlling pump mechanism114 or a fluid metering device. Controller 116 is preferably an ultralow-power (ULP) programmable controller which combines the necessaryprocessing power and peripheral set to control drug delivery through thepump mechanism 114, as well as to perform other optional system tasks,such as system or flow monitoring and communication with a host deviceor other external devices. Controller 116 is preferably embodied in anintegrated circuit (IC) or a “system on a chip” (SoC) including anyother circuitry, such as that necessary for communication with the hostdevice. SoC designs usually consume less power and have a lower cost andhigher reliability than the multi-chip systems that they replace. Byproviding a single chip system, overall size and area of the electroniccomponents is reduced and the arrangement of such components issimplified.

The IC or SoC, in an exemplary embodiment of the present invention, ispreferably provided on a flexible printed circuit board (PCB) 216, 316,416 and 516 as shown in FIGS. 2-5, respectively. Flexible PCBs are wellknown in the art. The specific construction and specifications of suchare outside the scope of the present disclosure. The flexible printedcircuit boards preferably provide wiring and support for connectingleads of various electrical components to the controller 116 and powersupply 118, such as pump mechanism 114, an automatic infusion needlemechanism 108, and an optional communication transceiver or bloodglucose sensor, as well as any other electronic component. The flexiblePCB, in each of the exemplary embodiments is preferably as flexible asthe exemplary lower cover of the medical device, so as not to inhibitthe overall flexibility of the medical device.

Power supply 118, in exemplary embodiments of the present invention,preferably comprises a thin flexible battery or batteries and/orsupercapacitors. Flexible, thin supercapacitors and lithium-polymerbatteries are well known in the art and are preferred in the exemplaryembodiments of the present invention. Power supply 118 may comprisedisposable or rechargeable power sources. One of ordinary skill in theart will appreciate that any known power supply that is thin andpreferably flexible is suitable for providing a power supply 118 inexemplary embodiments of the present invention. In an alternativeembodiment, a small rigid battery or batteries connected by flexibleconductors may also be used. The embodiments of power supply 118illustrated in FIGS. 2-5 are not limiting, and are provided merely todepict exemplary arrangements of a power supply in a medical deviceaccording to exemplary embodiments of the present invention. Powersupply 118, in an alternative embodiment of the present invention, maybe provided using energy harvesting techniques, alone or in combinationwith a standard power source, such as those disclosed in previouslyincorporated, co-pending U.S. Patent Application Serial No. 12/458,807.Power supply 118 is preferably connected to the flexible PCB usingflexible contacts. If multiple batteries are implemented, each of thebatteries may be connected to each other using flexible contacts and arepreferably spaced apart to promote optimum flexibility of medical device100.

Reservoir 106 in the exemplary embodiments illustrated in FIGS. 2-5,comprises a flexible pouch or bladder for storing a drug or othertherapeutic substance for delivery to the user. In an exemplaryembodiment, reservoir 106 is provided to the user pre-filled. Reservoir106 is preferably constructed from a flexible polymer that is compatiblewith the drug or substance to be stored therein. Various shapes anddimensions of reservoir 106 are shown in FIGS. 2-5. One of ordinaryskill in the art will understand that the specific illustrations are notlimiting, and the design of reservoir 106 may be altered depending onthe specific embodiment of medical device 100. Reservoir 106 ispreferably designed to be low-profile, so as to achieve a reducedoverall height/thickness of medical device 100. Reservoir 106 in theexemplary embodiments preferably holds a volume of drug that issufficient for the intended duration of use of the medical device. Insome cases, however, a large required volume of drug may be prohibitiveto an exemplary thin medical device. Alternate embodiments may include afill port and septum provided on the upper cover for enabling a user torefill reservoir 106, such as with a prefilled or fillable syringe, soas to enable a reduced surface area of the reservoir 106. In theseembodiments, reservoir 106 may also be fillable by the user prior touse.

Common patch pumps available in the art typically include a rigidcylindrical tube as a reservoir for housing a drug and comprise amechanism for displacing the volume within the reservoir to provide thedrug to a pumping or infusion mechanism, similar to a syringe andplunger or piston. Flexible reservoir 106 in the exemplary embodimentsof the present invention, however, introduces a unique challenge forsupplying the drug to the user, as the drug cannot be displaced from thereservoir using common techniques. As such, exemplary embodiments of thepresent invention employ pumping mechanisms or fluid metering devicesthat are capable of drawing a fluid or drug from a flexible reservoir106.

A first exemplary pump mechanism 614 or fluid metering device for use inexemplary embodiments of the present invention comprises a “thermalbubble micro pump”, as shown in FIGS. 6A-6C. A thermal resistor 602 isprovided near the distal end of a flow chamber 612 connected toreservoir 106. Thermal resistor 602 generates heat from an electricalcurrent selectively passed therethrough, which vaporizes a thermalexpansion fluid 606, generating a gas bubble and expanding flexiblemembrane 604. Flexible membrane 604 expands into the narrow flow chamber612 forcing a drop of a drug to the cannula, as shown in FIG. 6B. As thedrop of the drug is separated from the main body of fluid, thermalexpansion fluid 606 cools and condenses, thus flexible membrane 604reverts back to its original state shown in FIGS. 6A and 6C. As flexiblemembrane 604 relaxes to its original state, an additional volume of drugfrom reservoir 106 is drawn into the narrow flow chamber 612. Thisembodiment may also include at least one optional one-way check valvewithin flow chamber 612 for controlling displacement of the drug in theflow chamber. A first one-way check valve 608 is preferably provided inflow chamber 612 between reservoir 106 and the thermal resistor 602.This one-way check valve serves to block the flow of drug back intoreservoir 106 when flexible membrane 604 expands, as discussed above. Asecond optional one-way check valve 610 may be placed between thermalresistor 602 and the infusion cannula. The second one-way check valvepermits the flow of the drug only in one direction, to the user. Theone-way check valve 610 inhibits a flow of drug back into flow chamber612 as flexible membrane 604 retracts. Each of the optional one-waycheck valves may be substituted with an electronically controlled gateor valve or any other suitable mechanism for controlling the delivery ofdrug to the user, as would be appreciated by one of ordinary skill inthe art. The above process may be repeated indefinitely. The frequencyof expansion of flexible membrane 604 and the dimensions of the flowchamber can be controlled and designed to achieve a desired flow rate ofdrug to the user.

The process of vaporizing the thermal expansion fluid and thencondensing the expansion fluid makes up a complete expansion/contractioncycle necessary for expelling and drawing in a volume of the drug. Whenusing a single thermal resistor as shown in FIGS. 6A-6C, if continuousinfusion is required, the cooling/condensing process of the cycle mustbe accelerated. As such, an optional heat sink or heat pipe (not shown)may be provided for facilitating the condensing of the thermal expansionfluid. Any heat sink or heat pipe known in the art that is suitable foruse in the present invention may be provided, as would be appreciated byone of ordinary skill in the art.

Another embodiment may be provided with a plurality of thermal expansionunits placed in sequence within flow chamber 612 to effect a peristaltictype pump operation for controlling the flow of drug to the user, asshown in FIGS. 6D-6H. The operation of this embodiment is similar tothat discussed above with respect to FIGS. 6A-6B, except in thisembodiment an electrical current is passed sequentially to thermalresistors 602 a, 602 b and 602 c. An electrical current first providedto thermal resistor 602 a results in the expansion of flexible membrane604 a thus forcing a volume of drug toward the cannula. An electricalcurrent is then subsequently provided to the second thermal resistor 602b which results in the expansion of flexible membrane 604 b and furthermovement of a volume of drug toward the cannula. Next, an electricalcurrent provided to thermal resistor 602 c results in the expansion ofthermal membrane 604 c and expulsion of a volume of drug from flowchamber 612 into the cannula. By sequentially applying a current to eachthermal resistor, the pattern of expansion of the thermal membranesensures that the drug will move in the intended direction. This processis shown in the sequence of FIGS. 6E-6H. As the electrical current isremoved from each of the thermal resistors in sequence, the respectivethermal expansion fluid condenses and reverts back to the originalvolume, thus enabling an additional volume of drug to replace theexpelled volume. Since a plurality of thermal resistors are provided insequence, as the “down stream” thermal resistors are charged, thepreviously charged resistors begin to cool and condense the thermalexpansion fluid. As such, a previously charged thermal resistor has moretime to cool and condense the thermal expansion fluid, thus enabling acontinuous expansion/contraction cycle for effecting a continuous flowof drug to the user.

It should be appreciated by one of ordinary skill in the art, that thethermal expansion membranes 604 shown in FIGS. 6A-6H do not need to beintegral with or contained inside flow chamber 612. It may also bepreferable to provide the thermal expansion membranes separate andadjacent to flow chamber 612, so as to “pinch” the flow chamber uponexpansion. Pinching flow chamber 612 in this manner acts in a similarfashion to facilitate flow of the drug from the reservoir 106 to thecannula at the infusion site.

A one-way electronic gate 611 is shown for controlling the flow of drugto the user. In FIG. 6D, electronic gate 611 is shown as controlled in astate for preventing drug flow from entering the cannula. As anelectrical current is sequentially provided to thermal resistors 602a-602 c, electronic gate 611 is controlled to enable the flow of drug tothe cannula, as shown in FIGS. 6E-6G. Once the volume of drug isexpelled to the cannula, electronic gate 611 can be controlled toprevent the expelled volume of drug from being drawn back into flowchamber 612, as shown in FIG. 6H. The electronic gate 611 may besubstituted with a one-way check valve similarly provided in FIGS. 6A-6Cor any other means for controlling the flow of drug to the user, aswould be appreciated by one of ordinary skill in the art.

A second exemplary pump mechanism 714 using a similar concept describedabove, is illustrated in FIG. 7. In this embodiment, a holding chamber712 temporarily houses a volume of the drug to be delivered to the user,such as a bolus dose of insulin. The volume of drug enters holdingchamber 712 from reservoir 106 through a one way check valve 708. As anelectric current is applied to thermal resistor 702, thermal expansionfluid 706 is heated and expands, driving diaphragm 704 towards holdingchamber 712, thereby displacing the volume of drug in holding chamber712 and forcing the drug through a second one way check valve 710 to thedelivery cannula. The one way functionality of reservoir-side checkvalve 708 prevents the drug from being forced back into reservoir 106.Once thermal expansion fluid 706 cools and condenses, the force appliedby spring 715 is sufficient to drive diaphragm 704 away from holdingchamber 712, thereby increasing the volume of holding chamber 712, whichdraws an additional drug volume into holding chamber 712 from reservoir106. The cannula-side check valve 710 prevents the drug in the cannulafrom being drawn back into holding chamber 712. As would be appreciatedby one of ordinary skill in the art, one way check valves 708 and 710may be substituted with an electronically controlled gate such as thatshown in FIGS. 6D-6H and FIG. 9 or any other suitable means forcontrolling the flow of drug to the user.

The above process may repeat indefinitely and may be controlled toprovide a desired flow rate of the drug to the user. The volume of drugdelivered to the user is equivalent to the volume of drug that isdisplaced from holding chamber 712. The capacity of holding chamber 712and the amount of displacement caused by thermal expansion fluid 706 canbe designed and controlled to provide a desired infusion rate of thedrug to the user. In a modified embodiment of the system illustrated inFIG. 7, the thermal resistor and thermal expansion fluid may be replacedwith a solenoid shaft acting as a piston to control fluid displacementin holding chamber 712.

FIG. 8 illustrates a third exemplary pump mechanism 814 using similarconcepts as above. This embodiment utilizes a bellows fluid chamber 812that expands when drawing in a drug and compresses to expel the drugfrom the chamber. The expansion and compression of bellows chamber 812is driven by a thermal resistor 802 and thermal expansion fluid 806.When applied with an electric current, thermal resistor 802 heatsthermal expansion fluid 806 which vaporizes, expanding substantially,and applies a force to flexible membrane 804. The force imparted onflexible membrane 804 causes the membrane to expand, thus driving thebellows chamber 812 to a compressed state and expelling a volume of drugthrough one-way check valve 810. As the electric current is removed fromthermal resistor 802, thermal expansion fluid 806 condenses andalleviates the force on flexible membrane 804. As flexible membrane 804relaxes to its original state, bellows chamber 812 is pulled downward,as illustrated in FIG. 8, to an expanded state, thus drawing in anadditional volume of drug from reservoir 106 to be supplied to the useras desired.

Another exemplary pump mechanism 914 suitable for use in the presentinvention is illustrated in FIG. 9. This embodiment uses a Bellevillespring 904 or other suitable spring mechanism, such as a stamped leafspring, snap acting disk or flexure, to apply a force to flexiblereservoir 106. The pressure applied by the Belleville spring urges thedrug of reservoir 106 into a flow chamber 912. The pressurized drug isblocked from infusion into the user by an electronically controlled gateor metering valve 910, such as a solenoid controlled two-way fluidicvalve. Metering valve 910 is preferably controlled by controller 116 toenable a desired rate of drug flow to the user. Any metering valve orgate that may be electronically controlled to enable a desired rate offlow would be suitable in this embodiment of the present invention, aswill be understood by one of ordinary skill in the art, such as aferrofluidic gate or valve.

An additional exemplary pump mechanism 1014, for use in exemplaryembodiments of the present invention, comprises a simple diaphragm pump,as shown in FIG. 10, that draws a drug from a flexible reservoir (notshown). The diaphragm pump shown in FIG. 10 may be provided as a MEMSnanopump, available from Debiotech S.A., and generally comprises aseries of check valves 1008 and 1010 and a piezoelectric diaphragm 1004for realizing the flow of a drug or other substance housed in thereservoir. Piezoelectric diaphragm 1004 is positioned in the flowchannel 1012 and changes a size and shape to a deformed state in thepresence of an applied voltage. Diaphragm 1004 can be controlled torepeatedly switch from an undeformed state to a deformed state. Thisrepeated action functions as a pump to draw in a drug from reservoir 106through the first one-way check valve 1008 and expel the drug throughthe second one-way check valve 1010.

Other alternative pumping mechanisms and fluid metering devices may alsobe used in other embodiments of the present invention. One of ordinaryskill in the art will find it reasonable to implement any known pumpmechanism suitable in a wearable medical device for dispensing a liquidmedicament/drug to a user. Regardless of the chosen mechanism, it ispreferable that the pump mechanism be compact, lightweight, andlow-profile, so as not to unnecessarily increase the size and thicknessof the medical device.

The exemplary embodiments of the medical devices illustrated in FIGS.2-5 include a low-profile needle deployment mechanism 108 that may bemanually or automatically actuated for inserting an infusion cannulainto the user. The infusion cannula for use in the exemplary embodimentsof the present invention may comprise an infusion needle with a sideport for infusing the drug into the user or may alternatively comprise aflexible cannula inserted into the user with the aid of an insertionneedle. Additionally, a flexible cannula may be provided with asharpened tip to enable insertion of the flexible cannula into the user,thereby eliminating the need for a separate insertion needle. The tipmay optionally be hardened relative to the shaft. Other additionalexemplary embodiments may comprise an in-dwelling flexible, slottedsteel needle or a highly flexible torsion spring preferably providedwith a sharpened needle tip attached. Each of the slotted steel needleand torsion spring embodiments is also preferably encased in a Teflon®or Vialon® sheath or coating for sealing a fluid flow chamber within.More detailed descriptions may be found in co-pending commonly ownedU.S. Patent Application titled “Extended Use Medical Device” (attorneydocket number P-8618(55579)), filed on even date herewith, which ishereby incorporated by reference in its entirety. Of course any suitablefluid tight material could be used to form the sheath. The slotted steelneedle and torsion spring embodiments are flexible for increasedcomfort, yet provide a rigidity or column strength necessary forinsertion into the user's skin. The slotted steel needle is madeflexible due to the slots, and advantageously need not have a separatetip, but rather can be a unitary body having a sharpened tip. Thetorsion spring preferably includes a separate sharpened tip attached topenetrate the user's skin. Another exemplary embodiment of the presentinvention utilizes an array of micro-needles such as those implementedin Nanoject, an infusion device provided by Debiotech S.A. Any othersuitable infusion mechanism may be used in the exemplary embodiments ofthe present invention, as will be appreciated by one of ordinary skillin the art.

FIGS. 11A-11E and FIGS. 12A-12D illustrate exemplary embodiments of aneedle deployment mechanism 108 for use in exemplary embodiments of thepresent invention. FIG. 11A illustrates a manually actuated snap disk1102 for inserting an infusion needle or cannula into the user. A forceapplied to button 1101 urges snap disk 1102 from a convex position to aconcave position, driving the infusion cannula into the user. A secondexemplary embodiment of needle deployment mechanism 108, illustrated inFIG. 11B, uses a torsion spring 1105 for driving an infusion cannulainto the user. The infusion cannula in this embodiment comprises acircular formed needle 1104. Circular formed needle 1104 is constrainedto a circular path guided by torsion spring 1105. Prior to actuation,the needle is held in a ready position by a blocking arm 1106 attachedto a finger lever 1103. A user actuates needle deployment in thisembodiment by applying a force to an end of finger lever 1103 oppositeblocking arm 1106. When the user applies a downward force to lever 1103,blocking arm 1106 of the lever pivots away from a blocking position andenables torsion spring 1105 to drive the infusion needle into the user.

FIGS. 11C-11E illustrate another exemplary embodiment for use in thepresent invention that is especially suitable for the flexible, slottedsteel and torsion spring infusion needles discussed above. As shown inFIG. 11C, a flexible infusion needle 1122 is attached to a needlecarriage 1124. Needle carriage 1124 is held in a retracted, readyposition by a retention latch member 1126, which prevents needlecarriage 1124 from movement in the insertion direction. Infusion needledeployment may be actuated manually or automatically to displace theretention latch member 1126 from a blocking position. When retentionlatch 1126 is actuated, a compression spring 1128 drives needle carriage1124 in an insertion direction, as shown in FIG. 11D. After infusionneedle 1122 is inserted into the user, distal movement of needlecarriage 1124 is impeded by a chassis 1130 or housing containing theneedle deployment mechanism. FIGS. 11D and 11E illustrate the needledeployment mechanism of FIG. 11C with a guide sleeve 1132 for guidingthe flexible infusion needle 1122 into the user at a desired insertionangle. Additionally, guide sleeve 1132 provides additional integrity forthe flexible needle 1122 so as to resist kinking or other undesirabledeflection during deployment. As should be appreciated from FIGS. 11Dand 11E, guide sleeve 1132 can be configured within the medical deviceto enable deployment in various orientations with respect to the motionof needle carriage 1124. As such, the use of guide sleeve 1132 in theexemplary embodiments enables deployment of infusion needle 1122 intothe skin while minimizing the affect of the needle deployment mechanismon the overall profile of the medical device, by permitting thecarriages to move parallel to the skin.

FIGS. 12A-12D illustrate an exemplary embodiment of a needle deploymentmechanism similar to that described above with respect to FIG. 11C, forautomatically or manually driving a flexible cannula into a user withthe aid of an insertion needle. As shown in FIG. 12A, rigid insertionneedle 1202 is provided in the inner cavity of a flexible cannula 1204,with a sharpened tip extending from the end of the flexible cannula1204. The insertion needle and cannula are held in relative position toeach other by needle carriage 1206 and cannula carriage 1208. Needlecarriage 1206 and cannula carriage 1208 are held in a retracted, readyposition by a retention latch member 1212, which blocks cannula carriage1208 from movement in the insertion direction. Needle deployment may beactuated manually or automatically to displace the retention latchmember 1212 from a blocking position. When retention latch 1212 isactuated, a first compression spring 1210 drives cannula carriage 1208in an insertion direction, as shown in FIG. 12B. Needle carriage 1206 isengaged with cannula carriage 1208, thus the insertion motion of cannulacarriage 1208 drives needle 1202 into the user. After needle 1202 andcannula 1204 are inserted into the user, distal movement of cannulacarriage 1208 is impeded by a chassis or housing containing the needledeployment mechanism. As shown in FIG. 12C, at the point when distalmovement of cannula carriage is impeded, cannula carriage 1208 andneedle carriage 1206 become disengaged. At this point, a secondcompression spring 1211 drives the disengaged needle carriage 1206 in aproximal direction, thus withdrawing needle 1202 from the user whilecannula 1204 remains inserted, as shown in FIG. 12D.

In the exemplary embodiments discussed above, a user may manuallyactuate insertion of the cannula by asserting a force onto the actuationbutton, finger lever or other latch retention means provided on theexternal surface of the upper cover, as shown in FIGS. 2, 4 and 5A.Additionally, because of the thin flexible nature of the upper cover ofmedical device 100 in each of the embodiments discussed above, themanual actuation means may be provided within the housing and arepreferably actuated by applying a force to a specific area on theexternal surface of the upper cover.

The above needle deployment mechanisms are provided as exemplaryembodiments only. The embodiments shown in FIGS. 11 and 12 may alsoutilize motorized components or other electrical components, instead ofthe latch and spring mechanisms, for deploying an infusion cannula intoa user. One of ordinary skill in the art will understand that any needledeployment mechanism available in the art may be implemented inalternate embodiments of the present invention. It is preferable thatthe chosen needle mechanism comprises a relatively simple structure andbe low-profile so as to realize a thin, flexible medical device.

Additionally, any of the above needle deployment mechanisms may beslightly modified for deploying a transcutaneous analyte sensor orbiosensor, such as a blood glucose sensor, for use in alternateembodiments of medical device 100 for realizing continuous blood glucosemonitoring, as will be understood by one of ordinary skill in the art.For instance, the embodiment described in FIGS. 12A-12D may be providedfor inserting a biosensor 1222 positioned internal to an outer sleeve orneedle 1224 as shown in FIGS. 12E-12H. After deployment of the biosensor1222, the outer sleeve 1224 may retract, leaving the biosensor 1222exposed in the subcutaneous tissue of the user. As shown in FIG. 12E,the biosensor 1222 and needle 1224 are held in relative position to eachother by needle carriage 1225 and biosensor carriage 1223. Needlecarriage 1225 and biosensor carriage 1223 are held in a retracted, readyposition by a retention latch member 1212, which blocks biosensorcarriage 1223 from movement in the insertion direction. Sensordeployment may be actuated manually or automatically to displace theretention latch member 1212 from a blocking position. Of course itshould be understood that deployment may be caused by manual deployment,or electronically via an appropriate command received from a BGM or hostdevice. When retention latch 1212 is actuated, a first compressionspring 1226 drives the needle carriage 1225 and biosensor carriage 1223in an insertion direction, as shown in FIG. 12F. After biosensor 1222and needle 1224 are inserted into the user, distal movement of biosensorcarriage 1223 is impeded by a chassis or housing containing the needledeployment mechanism. As shown in FIG. 12G, at the point when distalmovement of biosensor carriage 1223 is impeded, needle carriage 1225 andbiosensor carriage 1223 become disengaged. At this point, a secondcompression spring 1227 drives the disengaged needle carriage 1225 in aproximal direction, thus withdrawing needle 1224 from the user whilebiosensor 1222 remains inserted, as shown in FIG. 12H.

FIGS. 12I-12J illustrate another deployment mechanism for an in-dwellingneedle and cannula for use in a medical device according to anembodiment of the present invention. Rather than being triggered as inpreviously described mechanisms, the needle deployment can be usercontrolled. That is, carriage 1225 is biased in a retracted position bycompression spring 1228. FIG. 12I shows the device in the retractedposition, such that needle 1229 and cannula 1230 do not protrude fromthe chassis. Carriage 1225 includes a manual actuator 1231 which isaccessible to the user. When the user moves manual actuator in thedirection of arrow ‘A’ with enough force to overcome the spring bias,the carriage 1225, along with needle 1229 and cannula 1230 move in thedirection of arrow ‘A’. Carriage 1225 also includes a finger latch 1232which mates with retention surfaces 1233 on retention latch 1234. Ascarriage 1232 moves in the direction of arrow ‘A’ interference betweenfinger latch 1232 and retention surfaces 1233 cause retention latch 1234to displace in the direction of arrow ‘B’. Finger latch 1232 andretention surfaces 1233 are shaped such that as the finger latch movespast each retention surface 1233, carriage 1225 is prevented from movingbackwards in the retracted direction. As the carriage moves in thedirection of arrow ‘A’ the needle and cannula protrude from the chassisand enter the user's skin surface. Cantilevered retention latch 1234 canbe flexed downward in the direction of arrow ‘B’ to release the carriage1225 an retract the needle and cannula. As will be appreciated by thoseof ordinary skill in the art, any suitable arrangement to releasecarriage 1225 by flexing retention latch 1234 downward may be employed.Such arrangements may include manual movement by the user via a deviceprovided on the exterior of the chassis, or automatic electronic releasevia an appropriate command on a PDM.

The combinations and arrangements of the above system components, asillustrated in FIGS. 2-5, are not intended to be limiting. One ofordinary skill in the art will appreciate that any of the abovecomponents may be combined and arranged as desired in any of the aboveexemplary embodiments for realizing a specific drug therapy tailored foreach user. Additional exemplary embodiments of medical device 100utilizing a combination of the above described components for realizinga specific drug therapy are illustrated in FIGS. 13 -15.

FIG. 13 illustrates a specific embodiment of a medical device forproviding two-drug therapy through a single infusion cannula provided ina single needle deployment mechanism 108. Reservoirs 106 a and 106 b areprovided in fluid communication with the single infusion cannula and arecontrolled by a single pumping mechanism 114 and an optional valvemechanism for controlling drug flow from each. Based on the number ofcomponents in this embodiment, the upper cover of the medical device isappropriately designed to include three lobes 1301, 1302 and 1303,radially extending from the central hub area 1304. Lobe 1301 preferablycontains needle deployment mechanism 108 while lobes 1302 and 1303preferably contain reservoirs 106 a and 106 b, respectively.

FIG. 14 illustrates another embodiment of a medical device for providingdrug therapy through a first and second infusion cannula provided byfirst and second needle deployment mechanism 108 a and 108 b. Eachinfusion cannula is manually or automatically actuated as describedabove. In one embodiment, the flexible upper cover may provide access toa push button for manually actuating each needle deployment mechanism108 and 108 b. Each infusion cannula may be in fluid connection with itsown reservoir 106 a or 106 b for supplying a two-drug therapy ifdesired. Alternatively, a single reservoir may be shared by eachinfusion cannula, thus enabling a back-up or secondary infusion cannulaif necessary.

FIG. 15 illustrates another embodiment for providing up to three-drugtherapy through a single infusion cannula. First and second reservoirs106 a and 106 b are shown as connected to a single pumping mechanism 114with an optional valve for controlling a drug flow from each.Additionally, a third reservoir 106 c may be provided directly to theinfusion cannula, as shown, for enabling a manual bolus dose of drug asdesired. Because of the thin, flexible nature of the upper cover of themedical device, a user may manually actuate a bolus dose by applying aforce to a specific area of the upper cover. The specific area ispreferably adjacent to the reservoir 106 c for holding a supply of drugto be provided in the bolus dose. The reservoir 106 c is preferablylocated in a particular lobe (1503) of the device so the user can pressthe lobe 1503 to effect a bolus dose. The force applied by the user mayexpel a volume of drug from the reservoir to be provided to the userthrough the infusion cannula. Optionally, the force applied by the usermay close an electrical contact that automatically actuates injection ofa bolus dose via an electronic pump mechanism and controller, as will beunderstood by one of ordinary skill in the art. In another embodiment,the medical device may be designed to provide only a bolus dose of oneor more drugs contained in one or more reservoirs through one or moreinfusion cannulas, as similarly provided above.

The additional embodiments shown in FIGS. 13-15 illustrate only a few ofthe myriad embodiments and arrangements enabled by the presentinvention, as will be appreciated by one of ordinary skill in the art.The specific combination of components described above, particularly thenumber of reservoirs and the drugs stored therein, may be chosen forproviding specific treatment to a user suitable for the user's medicalcondition, among other factors. Particularly, an exemplary medicaldevice may initially be provided for treatment of Type II diabetes byadministering only multiple daily injections or only bolus doses of asingle drug or a number of drugs. As a user's disease state progressesto increasing levels of insulin resistance, a similar medical devicewith another combination or arrangement of components may be used formore effective treatment.

Additionally, the features of the above exemplary embodiments may besimilarly provided in a number of applications and are not limited tothe above disclosure. Any other skin-surface, wearable, devices canutilize the above features and techniques for providing utmost comfortand convenience through maximum flexibility and conformity of thewearable device. In addition to the insulin patch pump devices disclosedherein, other drug therapy, such as for the treatment of rheumatoidarthritis, or the infusion of Human Growth Hormone, may ideally beprovided through a wearable medical device disclosed above, especiallyfor children or the elderly for whom the thin lightweight medical device100 is ideal.

A medical device, in any of the exemplary embodiments described above,may also be used in conjunction with a programmable drug delivery device1600, such as a programmable insulin pen, as shown in FIG. 16. In apreferred embodiment, a wearable medical device is configured to provideonly a preset, pre-programmable or programmable basal rate of infusion,whereas programmable drug delivery device 1600 is provided for infusingnecessary bolus dosages. While certain embodiments of the wearablemedical devices discussed above are capable of providing a bolus dose,some users may be more comfortable with and prefer to use a familiar peninjection device such as that shown in FIG. 16. Additionally, for someusers, drug therapy provided by an insulin pen device alone, may be aneffective treatment. Common mechanical insulin pen injection devicestypically require user interaction to accurately set a desired dosagefor the injection. Conventional mechanical pens generally include smalldosage graduations that may be difficult to see or accurately set. Assuch, a programmable insulin pen device 1600, in exemplary embodimentsof the present invention would eliminate the potential for dosage errorsresulting from a user's inability to properly operate the device.

In one embodiment of the present invention, when not in use, drugdelivery device 1600 preferably remains attached to a Personal DiabetesManager (PDM) 1602, Blood Glucose Monitor (BGM), or other device forcalculating a bolus dose. When a user instructs PDM 1602 to calculate abolus dose requirement, the PDM calculates the dose from either a basalrate infusion history or a user's blood glucose level, and automaticallyprograms the dose into drug delivery device 1600 without any furthercalculation, setting or adjustment required by the user. PDM 1602 mayalso comprise a sensing mechanism or other system for determining ablood glucose level, which it uses to calculate a desired bolus dose forthe user. This exemplary embodiment of the present invention reduces thenumber of steps necessary for infusion and reduces dosage errors causedby a user's inability to properly operate common, mechanical insulinpens.

Drug delivery device 1600 in an exemplary embodiment, preferablyincludes a replaceable insulin cartridge and may be cylindrical in form,similar to insulin pens that are commonly available. The dosemechanization typically located in the upper portion of common insulinpens is preferably replaced by a flex circuit which is wrapped aroundthe inner diameter of the pen barrel. A rechargeable battery may beprovided on the centerline of the barrel inside the flexible circuit.The replaceable insulin cartridge would be located in the lower portionof the pen, and a micro-pump is provided between the insulin cartridgeand a pen needle. Alternately, a linear actuator can be placed insidethe flexible circuit in line with the insulin vial. The linear actuatorapplies a force to drive the plunger in the vial, resulting in a bolusdose equal to the displaced volume of the plunger movement. Very smalllinear actuators are available and may advantageously used for thispurpose. One example is the Squiggle® linear actuator manufactured byNew Scale Technologies. The upper and lower portions of the penpreferably separate in order to replace the insulin cartridge, and whenreassembled, provide an electrical connection to the micro-pump. Eachtime drug delivery device 1600 is attached to PDM 1602, the rechargeablebattery in the delivery device 1600 may be charged, and an infusionhistory or blood glucose history that is stored in the pen mayautomatically be uploaded to the PDM 1602.

An exemplary embodiment of the present invention may provide drugdelivery device 1600 with the low cost components necessary forcommunicating via a personal area network as described in previouslyincorporated, co-pending U.S. application Ser. No. 12/458,807. Thisembodiment enables continued communication between the drug deliverydevice 1600 and PDM 1602 or a “smart” wearable medical device asdisclosed in the exemplary embodiments above. The “smart” medical deviceor PDM may automatically program drug delivery device 1600 each time abolus dose is calculated, as long as both are in physical communicationwith the user's body. A “smart” wearable medical device containing abiosensor, or otherwise in communication with a biosensor, may also becapable of providing bolus dosage requirements to the drug deliverydevice 1600 to be automatically programmed by the device based on auser's blood glucose level. Additionally, drug delivery device 1600 mayautomatically update via the personal area network, the PDM or “smart”medical device each time a bolus dose is administered to the user. Theabove embodiments provide a low-cost, intelligent device capable offurther enhancing the functionality of the exemplary wearable medicaldevices disclosed above, in an embodiment that is easy to use andfamiliar to many users requiring insulin therapy.

While the present invention has been shown and described with referenceto particular illustrative embodiments, it is not to be restricted bythe exemplary embodiments but only by the appended claims and theirequivalents. It is to be appreciated that those skilled in the art canchange or modify the exemplary embodiments without departing from thescope and spirit of the present invention.

What is claimed is:
 1. A wearable medical device for administering drugtherapy to a user, said medical device comprising: an integral housingcomprised of a flexible upper portion and a flexible lower portion,wherein said upper and lower portions comprise at least one recessextending inwardly from an outer edge of each of said upper and lowerportions.
 2. The medical device of claim 1, further comprising a secondrecess extending inwardly from an outer edge of each of said upper andlower portions at a location opposite the at least one recess.
 3. Themedical device of claim 2, wherein the first and second recesses definea flex region that separates a first area of the device from a secondarea of the device.
 4. The medical device of claim 3, wherein a firstsystem component is contained within the first area and a second systemcomponent is contained within the second area.
 5. A wearable medicaldevice for administering drug therapy to a user, said medical devicecomprising: an integral housing comprised of a flexible upper portionand a flexible lower portion, wherein said housing comprises a centralhub area with a plurality of lobes extending radially from said centralhub.
 6. The medical device of claim 5, wherein a first system componentis contained within a first lobe, and a second system component iscontained within a second lobe.
 7. The medical device of claim 6,wherein said first system component and said second system component areselected from the group consisting of: a reservoir for delivering a doseof a drug, a biosensor, a needle deployment mechanism, and acommunication transceiver.
 8. The medical device of claim 6, whereinsaid first system component and said second system component comprise afirst and second flexible reservoir, respectively.
 9. The medical deviceof claim 5, further comprising at least one adhesive pad attached to askin attachment side of said plurality of lobes.
 10. A method ofproviding a flexible, wearable medical device for administering drugtherapy to a user, said method comprising: preparing a housingcomprising an upper flexible portion and a lower flexible portion;providing within said housing, an infusion cannula in fluidcommunication with a reservoir for housing a drug to be administered tothe user and a fluid metering mechanism that meters a volume of the drugadministered through the infusion cannula; and forming the housing byconnecting the upper flexible portion to the lower flexible portionalong a perimeter of each.
 11. The method of claim 10, wherein theforming step is performed by sonically welding the upper flexibleportion to the lower flexible portion.